SHOW PROFILES shows how much time MySQL spends in various phases of query execution, but it isn’t a full-featured profile. By that, I mean that it doesn’t show similar phases aggregated together, doesn’t sort them by worst-first, and doesn’t show the relative amount of time consumed. I’ll profile the “nicer_but_slower_film_list” included with the Sakila sample [...]
Time for Zero Administration effort at MySQL ?
January 8, 2012 By 4 Comments
Preparing Optimizing MySQL Configuration talk for Percona Live in Washington,DC I noticed how many Variables did MySQL get over years – it is pushing 400 these days even if we do not count variables/options which do not have matching SHOW VARIABLES value, and settings done by changing tables rather than command line options (like much [...]
Improved InnoDB fast index creation
November 6, 2011 By 4 Comments
One of the serious limitations in the fast index creation feature introduced in the InnoDB plugin is that it only works when indexes are explicitly created using ALTER TABLE or CREATE INDEX. Peter has already blogged about it before, here I’ll just briefly reiterate other cases that might benefit from that feature: when ALTER TABLE [...]
Optimizing slow web pages with mk-query-digest
April 7, 2011 By 14 Comments
I don’t use many tools in my consulting practice but for the ones I do, I try to know them as best as I can. I’ve been using mk-query-digest for almost as long as it exists but it continues to surprise me in ways I couldn’t imagine it would. This time I’d like to share [...]
How to Identify Bad Queries in MySQL
January 10, 2011 By 16 Comments
Finding bad queries is a big part of optimization. A scientific optimization process can be simplified to “can anything be improved for less than it costs not to improve it? – if not, we’re done.” In databases, we care most about the work the database is doing. That is, queries. There are other things we [...]
Thinking about running OPTIMIZE on your Innodb Table ? Stop!
December 9, 2010 By 18 Comments
Innodb/XtraDB tables do benefit from being reorganized often. You can get data physically laid out in primary key order as well as get better feel for primary key and index pages and so using less space, it is just OPTIMIZE TABLE might not be best way to do it. If you’re running Innodb Plugin on [...]
Caching could be the last thing you want to do
July 24, 2010 By 14 Comments
I recently had a run-in with a very popular PHP ecommerce package which makes me want to voice a recurring mistake I see in how many web applications are architected. What is that mistake? The ecommerce package I was working with depended on caching. Out of the box it couldn’t serve 10 pages/second unless I [...]
Tuning InnoDB Concurrency Tickets
May 24, 2010 By 5 Comments
InnoDB has an oft-unused parameter innodb_concurrency_tickets that seems widely misunderstood. From the docs: “The number of threads that can enter InnoDB concurrently is determined by the innodb_thread_concurrency variable. A thread is placed in a queue when it tries to enter InnoDB if the number of threads has already reached the concurrency limit. When a thread [...]
Why you should ignore MySQL’s key cache hit ratio
February 28, 2010 By 28 Comments
I have not caused a fist fight in a while, so it’s time to take off the gloves. I claim that somewhere around of 99% of advice about tuning MySQL’s key cache hit ratio is wrong, even when you hear it from experts. There are two major problems with the key buffer hit ratio, and [...]
Community Events February-March
January 22, 2010 By 4 Comments
February and March as busy months for Community events. There’s MySQL University, Fosdem, the Seattle MySQL Meetup & Confoo.ca.
